Sentinel test: provide basic commands to access instances.
Prefix test file names with numbers to force exec order.
Sentinel test: info fields, master-slave setup, fixes.
Sentinel test: basic tests for MONITOR and auto-discovery.
Sentinel test: basic failover tested. Framework improvements.
Sentinel test: check reconfig of slaves and old master.
Sentinel test: ODOWN and agreement.
Sentinel test: check that role matches at end of 00-base.
Sentinel test: some reliability fixes to 00-base tests.
Sentinel: report instances role switch events.

This is useful mostly for debugging of issues.